The present invention relates to a seat reclining device and more specifically to an automotive seat reclining device capable of locking a seat back with improved strength.
An automotive seat is provided with a seat reclining device for locking a seat back at a desired angular position. The seat reclining device allows the seat back to pivot back and forth relative to a seat cushion when the angular position of the seat back is to be changed. At all other times, the seat back is held locked by the seat reclining device.
One type of seat reclining device employs toothed elements engageable with each other for locking the seat back.
The present invention is to provide a seat reclining device of such a type, which can lock a seat back with improved strength.
According to one aspect of the present invention, there is provided a seat reclining device, comprising: a base plate adapted to be secured to a seat cushion; a first toothed member adapted to be secured to a seat back and having first teeth; a center shaft with which the first toothed member is pivotally mounted on the base plate; a second toothed member having a pair of opposite first and second end portions and second teeth engageable with the first teeth, and pivotally mounted on the base plate at the first end portion thereof; a cam member pivotally mounted on the base plate so as to move the second toothed member in a direction to bring the second teeth into engagement with the first teeth for holding the seat back locked and in a direction to disengage the second teeth from the first teeth; a biasing member for biasing the cam member against the second toothed member in the direction to bring the second teeth into engagement with the first teeth; and a support for supporting the second end portion of the second toothed member so as to maintain engagement of the first teeth and the second teeth when the seat back is held locked.
According to another aspect of the present invention, there is provided a seat reclining device, comprising: a base plate adapted to be secured to a seat cushion; a first toothed member adapted to be secured to a seat back and having first teeth; a center shaft with which the first toothed member is pivotally mounted on the base plate; a second toothed member having a pair of opposite first and second end portions and second teeth engageable with the first teeth, and pivotally mounted on the base plate at the first end portion thereof; a cam member pivotally mounted on the base plate so as to move the second toothed member in a direction to bring the second teeth into engagement with the first teeth for holding the seat back locked and in a direction to disengage the second teeth from the first teeth; a spring member for urging the cam member to move the second toothed plate in the direction to bring the second teeth into engagement with the first teeth; and a control lever for controlling pivoting of the cam member, wherein at least one of the base plate and the cam member is provided with a support portion for supporting the second end portion of the second toothed member so as to maintain engagement of the first teeth and the second teeth when the seat back is held locked.